It is desirable to have a permanent manned presence in space for a number of reasons, including having a national laboratory in space and a continuously operational space observatory. While prior art space stations normally provide the desired permanent manned presence, they often require extensive on-orbit construction and numerous launches which restrict their general cost effectiveness. For instance, several prior art stations require many launches to provide a complete, operational space station. Furthermore, the assembly of the various modules forming prior art space stations may require significant EVA (extra vehicular activity) construction. If for some reason a flight must be aborted or is not launched within a certain time period, prior art space stations may have construction timing problems. Prior art space station designs do not always facilitate the addition of supplemental structure, such as pressurized living and laboratory areas or electrical power production, which may be required at a future time.
Somewhat older prior art single-launch space station designs may not be adaptable for fully efficient use with presently available heavy-lift launch vehicles. Recently developed single-launch space station designs are substantially limited in pressurized living volume so that the entire space station may fit into the cargo bay of the Shuttle Orbiter. Such designs may also require significant EVA construction. The cargo bay of the Shuttle Orbiter is generally limited to a medium size payload weighing approximately 35,000 pounds. This compares to the heavy lifting power of the Shuttle Orbiter launch vehicle which may lift a comparatively heavy payload in the general range of about 180,000 pounds.
Examples of prior art space stations and heavy-launch vehicles include U.S. Pat. No. 5,143,327 to James A. Martin which discloses a heavy-launch vehicle for placing a payload into Earth orbit having a preferred payload entry module adapted to be docked to a space station.
U.S. Pat. No. 5,184,789 to Buzz Aldrin discloses a space station facility having a plurality of elongated members which form a cuboctahedral-shaped structure surrounding a central pressurized command module. The space station facility may orbit as a space station, or be used as part of a larger space station.
U.S. Pat. No. 4,792,108 to Stephen M. Bull discloses a space station adapted to be launched in its entirety in a single voyage as cargo in the hold of the Shuttle Orbiter. It is deployed in space and erected to form a structure with a number of modules held in fixed relation to each other.
U.S. Pat. No. 4,872,625 to Charles C. Filley discloses a universal module assembly including a pressure vessel having cylindrical side walls and curved end surfaces. A rigid external supporting framework is attached to the exterior of and surrounds the pressure vessel. The framework includes a main body portion disposed around cylindrical side walls and having end portions covering the curved end surfaces of the pressure vessel.
U.S. Pat. No. 3,300,162 to O. E. Maynard et al. discloses three elongate rigid cylindrical modules, each of which, when the station is fully erected, extends radially outwardly from a central hub structure that includes hangar and docking facilities for spacecraft.
U.S. Pat. No. 3,210,026 to Erling Frisch discloses an expandable space platform Comprising a pair of outer cabins joined together by a telescopic arrangement and preferably having a main central cabin incorporated in the structure between the outer cabins. The outer cabins can include living quarters with suitable conditions for crew and storage, operating machinery, test equipment, and the like.
Consequently, there remains the need for an improved space station requiring little EVA (extra-vehicular activity) for assembly, that offers a complete and comparatively large pressurized living and working volume with integrated essential subassemblies, and that is suitable for a single launch at reduced levels of capital investment.